CN115368202A - Benzene extraction process and extraction system for coking pure benzene - Google Patents
Benzene extraction process and extraction system for coking pure benzene Download PDFInfo
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- CN115368202A CN115368202A CN202211008818.9A CN202211008818A CN115368202A CN 115368202 A CN115368202 A CN 115368202A CN 202211008818 A CN202211008818 A CN 202211008818A CN 115368202 A CN115368202 A CN 115368202A
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- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 title claims abstract description 651
- 238000000605 extraction Methods 0.000 title claims abstract description 71
- 238000004939 coking Methods 0.000 title claims abstract description 61
- 239000002904 solvent Substances 0.000 claims abstract description 77
- 238000011084 recovery Methods 0.000 claims abstract description 30
- 238000000895 extractive distillation Methods 0.000 claims description 24
- 238000002347 injection Methods 0.000 claims description 22
- 239000007924 injection Substances 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 19
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 18
- 150000004945 aromatic hydrocarbons Chemical class 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 16
- 238000005194 fractionation Methods 0.000 claims description 12
- 238000010992 reflux Methods 0.000 claims description 10
- 238000009833 condensation Methods 0.000 claims description 7
- 230000005494 condensation Effects 0.000 claims description 7
- 238000005507 spraying Methods 0.000 claims description 7
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 238000004064 recycling Methods 0.000 claims description 4
- 230000007704 transition Effects 0.000 claims description 2
- 238000004891 communication Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 18
- 238000000926 separation method Methods 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000005265 energy consumption Methods 0.000 abstract description 3
- 239000000126 substance Substances 0.000 abstract description 2
- -1 fractionating tower Chemical compound 0.000 abstract 1
- 239000012071 phase Substances 0.000 description 25
- 239000007789 gas Substances 0.000 description 19
- 239000007791 liquid phase Substances 0.000 description 16
- 230000001976 improved effect Effects 0.000 description 12
- 239000007788 liquid Substances 0.000 description 7
- 230000001174 ascending effect Effects 0.000 description 5
- 239000007792 gaseous phase Substances 0.000 description 5
- YJTKZCDBKVTVBY-UHFFFAOYSA-N 1,3-Diphenylbenzene Chemical group C1=CC=CC=C1C1=CC=CC(C=2C=CC=CC=2)=C1 YJTKZCDBKVTVBY-UHFFFAOYSA-N 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 238000009835 boiling Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 239000008258 liquid foam Substances 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 238000005292 vacuum distillation Methods 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
- B01D3/324—Tray constructions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
- B01D3/40—Extractive distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
- C07C7/05—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds
- C07C7/08—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds by extractive distillation
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Water Supply & Treatment (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The application discloses coking pure benzene's benzene extraction technology relates to chemical industry technical field, including BTXS fraction prefractionation, BTXS fraction entering fractionating tower is prefractionated, and benzene front cut and benzene are separated and the extraction rectification of subsequent benzene front cut and benzene, coking pure benzene and solvent separation and coking pure benzene collection from the top of fractionating tower. The application also discloses a benzene extraction system of coking pure benzene, including fractionating tower, extraction rectifying column, solvent recovery tower and the product storage tank that communicates the setting in proper order. The application has the effects of reducing the difficulty of extraction and rectification, improving the extraction effect, reducing the energy consumption of the production cost and improving the purity of the coking pure benzene.
Description
Technical Field
The application relates to the technical field of chemical industry, in particular to a benzene extraction process of coking pure benzene and an extraction system thereof.
Background
The crude benzene hydrofining is composed of units such as hydrofining, extractive distillation, aromatic hydrocarbon refining and public facilities. Heavy components above C9 of crude benzene are firstly removed in a hydrofining unit, and then the crude benzene is subjected to multi-stage evaporation and two-stage hydrogenation treatment to obtain a triphenyl fraction, namely BTXS fraction, which is sent to an extractive distillation unit.
During the extractive distillation, a triphenyl extraction process is usually adopted, and BTXS fraction enters an extractive distillation tower for extractive distillation to remove non-aromatic hydrocarbons; the rich solvent without the non-aromatic hydrocarbon enters a solvent recovery tower from the bottom of the extraction and rectification tower, and the pure aromatic hydrocarbon and the solvent are separated by the rich solvent under the negative pressure rectification of the solvent recovery tower; pure aromatic hydrocarbon enters a reflux tank after being condensed at the top of the tower, and then is sent into a benzene tower through pressurization, and the separation of coking pure benzene, toluene, xylene and C8 fraction is realized in the benzene tower.
However, in the extraction process of the triphenyl, because the BTXS fraction has more components, great operation difficulty and poor separation effect, the purity of the finally fractionated coking pure benzene is low.
Disclosure of Invention
In order to solve the problems that the separation effect of coking pure benzene in a triphenyl extraction process is poor and the purity of fractionated coking pure benzene is low, the application provides a benzene extraction process of coking pure benzene and an extraction system thereof.
In a first aspect, the application provides a process for extracting benzene from coking pure benzene, which adopts the following technical scheme:
a process for extracting benzene from coking pure benzene comprises the following steps:
pre-fractionation of BTXS fraction: the BTXS fraction enters a fractionating tower for prefractionation, benzene front fraction and benzene are separated from the tower top of the fractionating tower, and toluene and later components are separated from the tower bottom of the fractionating tower;
benzene front fraction and extractive distillation of benzene: benzene and benzene which are obtained by pre-fractionating the BTXS fraction enter an extraction and rectification tower for extraction and rectification, non-aromatic hydrocarbons are separated from the top of the extraction and rectification tower, and a benzene-rich solvent is separated from the bottom of the extraction and rectification tower;
separating coked pure benzene from a solvent: the benzene-rich solvent obtained from the benzene front fraction and the benzene extraction and rectification process enters a solvent recovery tower, and the coking pure benzene is separated from the top of the solvent recovery tower after rectification;
collecting coking pure benzene: the coking pure benzene separated from the solvent recovery tower is sent into a product storage tank after condensation and pressurization treatment.
By adopting the technical scheme, the benzene front fraction and the benzene in the BTXS fraction are pre-fractionated through the fractionating tower and are separated out in advance, so that the components participating in subsequent extraction and rectification and solvent recovery and rectification are reduced, the difficulty of extraction and rectification is reduced, the extraction effect is improved, the integral boiling points of the benzene front fraction and the benzene components are lower, the operation temperature is low, the energy consumption is reduced, and the purity of the coking pure benzene is greatly improved.
Optionally, the benzene front fraction and the benzene are separated from the top of the fractionating tower, and then enter a reflux tank after condensation treatment, and then enter an extractive distillation tower after pressurization treatment.
By adopting the technical scheme, the benzene front fraction and the benzene enter the extraction and rectification tower after being condensed and pressurized, the volatile non-aromatic hydrocarbon is thickened in a gas phase after pressurization, and the benzene which is difficult to volatilize is dissolved in the solvent for thickening, so that the separation effect of the non-aromatic hydrocarbon and the benzene in the extraction and rectification tower is improved, the content of the benzene in the solvent is ensured, and the purity of the final coking pure benzene product is improved.
Optionally, the benzene-rich solvent enters a solvent recovery tower, and the coking pure benzene is separated after vacuum rectification.
By adopting the technical scheme, the vacuum rectification is favorable for separating the coking pure benzene from the benzene-rich solvent, the relative volatility between the coking pure benzene and the solvent is increased, and the purity of the coking pure benzene after rectification is further ensured.
Optionally, the benzene-rich solvent is used for separating the coked pure benzene and then converting the coked pure benzene into a benzene-poor solvent, and the benzene-poor solvent is cooled and then recycled to the extractive distillation tower for recycling.
By adopting the technical scheme, the benzene-rich solvent is circularly transferred into the rectifying tower again for repeated use after being converted into the benzene-poor solvent, so that the utilization rate of the solvent is improved, and the production cost is effectively saved.
In a second aspect, the present application provides a benzene extraction system for coking pure benzene, which adopts the following technical scheme:
the utility model provides a coking pure benzene's benzene extraction system, includes the fractionating tower, extraction rectifying column, solvent recovery tower and the product storage tank that communicate the setting in proper order, the fractionating tower intercommunication has the access passage of BTXS fraction, the fractionating tower is arranged in separating benzene front cut and benzene from BTXS fraction, the extraction rectifying column is used for carrying out the rectification with benzene front cut and benzene, separates non-aromatic hydrocarbon and rich benzene solvent, the solvent recovery tower is used for fractionating the coking pure benzene of rich benzene solvent, the product storage tank is used for storing coking pure benzene.
By adopting the technical scheme, the BTXS fraction enters the fractionating tower through the access passage, prefractionation treatment is carried out in the fractionating tower, the benzene front fraction and benzene are separated from the BTXS fraction in advance, then the benzene front fraction and the benzene are further fractionated, non-aromatic hydrocarbon is separated out, then a benzene-rich solvent is sent into the solvent recovery tower, finally, the fractionated coking pure benzene is stored in the product storage tank, devices required for coking pure benzene extraction are reduced, the production cost is reduced, the benzene front fraction and the benzene are narrow in component, the extraction difficulty is reduced, the extraction effect is enhanced, and the purity of the coking pure benzene is improved.
Optionally, a plurality of layers of tower plates are arranged in the fractionating tower along the height direction of the fractionating tower, and the tower plates are of a flow-through structure.
By adopting the technical scheme, the column plate with the cross-flow structure reduces the flow resistance of gas phase and liquid phase in the fractionating tower, improves the mass transfer efficiency, has high production capacity, reduces pressure drop, is not easy to cause blockage and precipitation, and ensures effective separation of benzene front fraction and benzene components.
Optionally, the column plate is including the bottom plate, a plurality of groups of clearing holes have been seted up on the bottom plate, the clearing hole is rectangular form waist type hole, the rigid coupling has the fagging on the bottom plate, the rigid coupling has a plurality of first baffles on the fagging, first baffle is located the clearing hole top, just the cross-section of first baffle is the V-arrangement structure, the V-arrangement opening of first baffle is aimed at the clearing hole.
By adopting the technical scheme, the passing area of the single benzene fraction extraction is enhanced by the long strip-shaped kidney-shaped holes, the mass transfer area is increased, the mass transfer efficiency is improved, and the V-shaped structure of the first baffle plate enables the ascending gas phase and the descending liquid phase to be lifted, crushed, mixed and finally separated in the horizontal direction during mixed mass transfer, so that the mass transfer effect is enhanced, and the entrainment is reduced.
Optionally, one side of the first baffle, which is far away from the bottom plate, is further provided with a plurality of second baffles, the second baffles are fixedly connected to the supporting plate, the cross sections of the second baffles are of V-shaped structures, and the V-shaped openings of the second baffles and the V-shaped openings of the first baffles are arranged in a staggered manner.
By adopting the technical scheme, the gas phase continuously rises from the position between the adjacent first baffles after passing through the first baffles and impacts the second baffle, so that the mass transfer of the gas phase and the liquid phase is more thorough, the separation of the gas phase and the liquid phase is further promoted, and entrainment is reduced.
Optionally, the bottom plate has the injection cover towards one side rigid coupling of first baffle, the injection cover is the loop configuration that both ends link up, the one end of injection cover is aimed at the clearing hole, leave the clearance between injection cover and the bottom plate, be provided with the connection foot on the injection cover, connect the foot with bottom plate fixed connection.
Through adopting above-mentioned technical scheme, the injection cover sets up in the position department of clearing hole, and the liquid phase is left along the clearance department of injection cover and bottom plate, is carried by the ascending gaseous phase and draws, breaks and mixes, and when the gas-liquid mixture phase runs into first baffle and returns, renews the mass transfer area once more in the injection cover, improves the mass transfer effect.
Optionally, the spraying cover is in transition arrangement in a shape of a throat from one end close to the bottom plate to one end close to the first baffle plate.
Through adopting above-mentioned technical scheme, when the gaseous phase rises in spraying the cover, the flow cross-section diminishes gradually, and flow strength increases gradually, strengthens the impact injection intensity of gaseous phase at the rise in-process, makes gaseous phase and liquid phase more thorough renewal mass transfer, has further promoted the mass transfer effect.
In summary, the present application includes at least one of the following beneficial technical effects:
1. through setting up BTXS fraction prefractionation, the extractive distillation of benzene front cut and benzene, the first benzene extraction technology of coking pure benzene and solvent separation and coking pure benzene collection, carry out prefractionation through the fractionating tower with benzene front cut and benzene in the BTXS fraction and come out in advance, reduced and participated in the follow-up extractive distillation, component in the solvent recovery rectification, reduced the degree of difficulty of extractive distillation, promoted the extraction effect, and the whole boiling point of benzene front cut and the component of benzene is lower, operating temperature is low, and the energy consumption has been reduced simultaneously, the purity of obtaining of coking pure benzene has been improved greatly.
2. Through setting up fractionating tower, extraction rectifying column, solvent recovery tower and the product storage tank that communicates in proper order, reduced the required device that the pure benzene of coking extracted, reduced manufacturing cost, and the component of fraction and benzene is narrow before the benzene, reduced the extraction degree of difficulty, strengthened the extraction effect, promoted the purity of the pure benzene of coking.
3. Through being provided with injection cover, first baffle and second baffle on the column plate, the liquid phase is in the decline in-process, is carried by ascending gaseous phase and is carried, broken, mixes correlation, has improved mass transfer effect and mass transfer efficiency greatly, and has effectively reduced the phenomenon that the mist foam smugglies secretly in the fractionating tower, has guaranteed that the effective prefractionation of benzene fraction and benzene goes on.
Drawings
FIG. 1 is a process flow diagram of a process for the extraction of benzene from coking pure benzene in an example of the present application;
FIG. 2 is a schematic diagram of the configuration of trays within a fractionation column in an embodiment of the present application;
FIG. 3 is a cross-sectional view of the structure of a tray in a fractionation column in an embodiment of the present application.
Description of reference numerals: 1. a fractionating column; 11. a column plate; 111. a base plate; 1111. through the aperture; 112. a supporting plate; 113. a first baffle; 114. a second baffle; 115. a spray hood; 1151. a connecting pin; 2. a reflux tank; 3. an extractive distillation column; 4. a solvent recovery column; 41. a return path; 5. and (7) a product storage tank.
Detailed Description
The present application is described in further detail below with reference to figures 1-3.
The embodiment of the application discloses a benzene extraction process of coking pure benzene, which refers to fig. 1 and comprises the following steps:
BTXS fraction pre-fractionation: the BTXS fraction enters a fractionating tower 1 for pre-fractionation, benzene front fraction and benzene are separated from the top of the fractionating tower 1, and toluene and the subsequent components are separated from the bottom of the fractionating tower 1; the benzene front fraction and benzene are separated from the top of the fractionating tower 1, enter a reflux tank 2 after condensation treatment, and then enter an extraction rectifying tower 3 after pressurization treatment.
Benzene front fraction and benzene extractive distillation: benzene front fraction obtained by pre-fractionating the BTXS fraction and benzene enter an extraction rectifying tower 3 for extraction and rectification, non-aromatic hydrocarbon is separated from the top of the extraction rectifying tower 3, and a benzene-rich solvent is separated from the bottom of the extraction rectifying tower 3;
separating coked pure benzene from a solvent: benzene-rich solvent obtained from the benzene front fraction and the benzene extractive distillation process enters a solvent recovery tower 4, and the benzene-rich solvent is subjected to vacuum distillation to separate coked pure benzene from the top of the solvent recovery tower 4; the benzene-rich solvent is used for separating coked pure benzene and then converting the coked pure benzene into a benzene-poor solvent, and the benzene-poor solvent is cooled and then recycled to the extractive distillation tower 3 for recycling;
collecting coking pure benzene: the coking pure benzene separated from the solvent recovery tower 4 is sent to a product storage tank 5 for storage after being condensed and pressurized.
The implementation principle of the benzene extraction process of coking pure benzene in the embodiment of the application is as follows: when the BTXS fraction is subjected to extraction and fractionation treatment, the BTXS fraction firstly enters a fractionating tower 1, benzene front fraction and benzene are firstly separated out, then the benzene front fraction and the benzene are subjected to condensation and pressurization treatment and then sent into an extraction and rectification tower 3 for rectification, non-aromatic hydrocarbon is separated out, the benzene is dissolved in a solvent to form a benzene-rich solvent, and finally the benzene-rich solvent is subjected to reduced pressure rectification to separate out coking pure benzene. The pre-fractionation treatment of the fractionating tower 1 reduces the components which subsequently participate in the extraction and rectification, effectively reduces the difficulty of rectification and improves the purity of the coking pure benzene.
The embodiment of the application also discloses a benzene extraction system of coking pure benzene, refer to fig. 1, including the fractionating tower 1, reflux drum 2, extraction rectifying tower 3, solvent recovery tower 4 and the product storage tank 5 that communicate the setting in proper order, in the BTXS fraction that produces after the coking crude benzene hydrotreating firstly passes through access channel and gets into fractionating tower 1, carry out the prefractionation in fractionating tower 1, separate out benzene front cut and benzene from the top of fractionating tower 1, separate out toluene and the component behind the toluene from the bottom of fractionating tower 1, benzene front cut and the benzene that separate out get into reflux drum 2.
In order to further enhance the separation effect of benzene front fraction and benzene in the fractionating tower 1, a corresponding tower plate 11 is arranged in the fractionating tower 1, the tower plate 11 is of a cross-flow structure, and a plurality of layers of tower plates 11 are regularly arranged along the height direction of the fractionating tower 1.
Referring to fig. 2 and 3, the tray 11 includes a bottom plate 111, the bottom plate 111 is a flat plate structure, the bottom plate 111 is fixedly installed in the fractionating tower 1, the bottom plate 111 is provided with a plurality of sets of through holes 1111, the through holes 1111 are elongated kidney-shaped holes, the gas phase ascends in the fractionating tower 1 through the through holes 1111, the liquid phase descends in the fractionating tower 1 through the through holes 1111, and the gas phase and the liquid phase carry out mass transfer with each other near the positions of the through holes 1111.
A plurality of groups of spraying hoods 115 are arranged on one side of the bottom plate 111, the spraying hoods 115 are arranged corresponding to the passing holes 1111, each spraying hood 115 is of an annular structure with two penetrating ends, and one end, facing the bottom plate 111, of each spraying hood 115 is identical to the passing holes 1111 in shape and is aligned with the passing holes 1111. The spray cap 115 is further provided with a connection leg 1151 at a position facing the bottom plate 111, the connection leg 1151 is fixedly connected to the bottom plate 111, and the connection leg 1151 is provided at an interval such that a gap is left between the spray cap 115 and the bottom plate 111, and the liquid phase on the bottom plate 111 flows into the passage 1111 from the gap and descends.
A plurality of supporting plates 112 are fixedly connected to the bottom plate 111, the supporting plates 112 are vertically arranged, first baffle plates 113 are fixedly connected between the supporting plates 112, and the first baffle plates 113 are positioned on one side, far away from the bottom plate 111, of the injection hood 115. The first baffle 113 has a V-shaped cross section, and the V-shaped opening of the first baffle 113 is aligned with the opening of the spray hood 115 away from the base plate 111.
The gas phase and the liquid phase are subjected to contact mass transfer in the injection cover 115, the gas phase ascending on the lower tray 11 ascends through the injection cover 115, the liquid phase on the bottom plate 111 flows downwards from the through hole 1111 through the gap between the injection cover 115 and the bottom plate 111, and is pulled, crushed and mixed by the ascending gas phase to impact on the first baffle 113, so that a first mass transfer process is carried out; when the gas-liquid mixed phase impacts the V-shaped inner part of the first baffle 113 to turn back, the gas-liquid contact surface is updated, and a second mass transfer process is carried out; then the folded gas-liquid mixed phase is sprayed out from the V-shaped edge of the first baffle 113, the gas-liquid mixed phases at the adjacent first baffle 113 are collided and crushed, a new contact surface is formed again, and the third mass transfer process is completed. And the gas-liquid mixed phase is horizontally sprayed out from the V-shaped edge, the initial speed of the liquid phase in the vertical direction is reduced, the entrainment amount of liquid foam is reduced, and entrainment is reduced. Furthermore, the injection cover 115 is transitionally arranged from one end close to the bottom plate 111 to one end close to the first baffle 113 in a necking shape, so that the impact lifting strength of the gas phase in the rising process is enhanced, and the mass transfer effect is improved.
After the gas phase and the liquid phase pass through the first baffle 113, the gas phase is primarily separated, the gas phase continues to rise, and the liquid phase descends. In order to further enhance the mass transfer effect and reduce entrainment, a second baffle 114 is further disposed on a side of the first baffle 113 away from the injection hood 115, two sides of the second baffle 114 are respectively fixedly connected to the supporting plates 112, and the second baffle 114 is located between adjacent first baffles 113. The second baffle 114 is provided with a structure having a V-shaped cross section, which is the same as that of the first baffle 113, and the V-shaped opening of the second baffle 114 is aligned with a position between the adjacent first baffles 113, that is, is staggered with the V-shaped opening of the first baffle 113. The gas phase passing through the first baffles 113 carries a small amount of liquid phase, rises from the gaps between adjacent first baffles 113, and then continues to impinge on the second baffles 114 for impingement mass transfer while further reducing entrainment in the gas phase.
The gas phase rises after passing through the second baffle 114, completing the pre-fractionation of the BTXS fraction. Referring to fig. 1, a benzene front cut of a gas phase and benzene are separated from the top of a fractionation column 1 and then introduced into a reflux drum 2 to be condensed and pressurized. The extractive distillation tower 3 is used for rectifying the pressurized benzene front fraction and benzene, non-aromatic hydrocarbon is separated from the top of the extractive distillation tower 3, and the bottom of the extractive distillation tower 3 is a benzene-rich solvent.
Referring to fig. 1, the solvent recovery tower 4 is used for performing vacuum rectification on a benzene-rich solvent, the benzene-rich solvent is subjected to vacuum rectification, coked pure benzene is separated from the top of the solvent recovery tower 4, the benzene-rich solvent is converted into a benzene-poor solvent after losing pure benzene, a reflux passage 41 is communicated between the solvent recovery tower 4 and the extractive distillation tower 3, and the benzene-poor solvent is separated from the bottom of the solvent recovery tower 4, cooled through the reflux passage 41, and then recovered into the extractive distillation tower 3 again for recycling. After the coking pure benzene is separated from the solvent recovery tower 4, the coking pure benzene is finally sent to a product storage tank 5 for storage through condensation and pressurization treatment, and the extraction and processing of the coking pure benzene are completed.
The implementation principle of a benzene extraction system of coking pure benzene in this application embodiment is: when the BTXS fraction is subjected to separation and coking of pure benzene, the BTXS fraction is firstly sent into a fractionating tower 1 for pre-fractionation treatment, a tower plate 11 in the fractionating tower 1 is specially arranged for benzene extraction, and a strip-shaped waist-shaped hole-shaped through hole 1111 strengthens the passing area of single benzene fraction extraction, increases a mass transfer space, reduces the flow resistance of gas-liquid two phases in the fractionating tower 1, and improves the mass transfer efficiency; the cooperation of injection cover 115, first baffle 113 and second baffle 114 sets up, and mass transfer process has further strengthened the mass transfer effect and has reduced the entrainment and smuggle many times, under the prerequisite that guarantees that the board flux is big, has improved anti-blocking ability, has improved effect and the efficiency that benzene front cut and benzene prefractionation were followed from the BTXS fraction. The separated benzene front fraction and benzene pass through an extractive distillation tower 3 to separate out non-aromatic hydrocarbons, and finally the coking pure benzene is separated out through a solvent recovery tower 4 and sent to a product storage tank 5 for storage.
The specific embodiments are only for explaining the present application and are not limiting to the present application, and those skilled in the art can make modifications to the embodiments without inventive contribution as required after reading the present specification, but all the embodiments are protected by patent law within the scope of the claims of the present application.
Claims (10)
1. A process for extracting benzene from coking pure benzene is characterized by comprising the following steps: the method comprises the following steps:
BTXS fraction pre-fractionation: the BTXS fraction enters a fractionating tower (1) for prefractionation, benzene front fraction and benzene are separated from the top of the fractionating tower (1), and toluene and subsequent components are separated from the bottom of the fractionating tower (1);
benzene front fraction and benzene extractive distillation: benzene front fraction obtained by pre-fractionating the BTXS fraction and benzene enter an extraction rectifying tower (3) for extraction and rectification, non-aromatic hydrocarbon is separated from the top of the extraction rectifying tower (3), and a benzene-rich solvent is separated from the bottom of the extraction rectifying tower (3);
separating coking pure benzene from solvent: the benzene-rich solvent obtained from the benzene front fraction and the benzene extraction and rectification process enters a solvent recovery tower (4), and the coked pure benzene is separated from the top of the solvent recovery tower (4) after rectification;
collecting coking pure benzene: the coking pure benzene separated from the solvent recovery tower (4) is sent into a product storage tank (5) after condensation and pressurization treatment.
2. The process of claim 1 for the extraction of benzene from coking pure benzene, wherein: the benzene front fraction and benzene are separated from the top of the fractionating tower (1), enter a reflux tank (2) through condensation treatment, and then enter an extraction rectifying tower (3) after pressurization treatment.
3. The process of claim 2, wherein the benzene extraction process comprises the following steps: and after the benzene-rich solvent enters a solvent recovery tower (4), carrying out vacuum rectification and then separating the coking pure benzene.
4. The process of claim 1 for the extraction of benzene from coking-pure benzene, wherein: the benzene-rich solvent is used for separating coked pure benzene and then converting the coked pure benzene into a benzene-poor solvent, and the benzene-poor solvent is cooled and then recycled to the extraction rectifying tower (3) for recycling.
5. A benzene extraction system of coking pure benzene, its characterized in that: the extraction process of any one of claims 1 to 4, comprising a fractionating tower (1), an extractive distillation tower (3), a solvent recovery tower (4) and a product storage tank (5) which are arranged in sequence in communication, wherein the fractionating tower (1) is communicated with an access passage of the BTXS fraction, the fractionating tower (1) is used for separating the benzene front fraction and the benzene from the BTXS fraction, the extractive distillation tower (3) is used for rectifying the benzene front fraction and the benzene and separating the non-aromatic hydrocarbons from the benzene-rich solvent, the solvent recovery tower (4) is used for fractionating the coking pure benzene of the benzene-rich solvent, and the product storage tank (5) is used for storing the coking pure benzene.
6. A benzene extraction system for coking pure benzene according to claim 5, characterized in that: a plurality of layers of tower plates (11) are arranged in the fractionating tower (1) along the height direction of the fractionating tower, and the tower plates (11) are of a cross-flow structure.
7. The system of claim 6, wherein the system further comprises: column plate (11) is including bottom plate (111), a plurality of groups of clearing hole (1111) have been seted up on bottom plate (111), clearing hole (1111) are rectangular form waist type hole, the rigid coupling has fagging (112) on bottom plate (111), the rigid coupling has first baffle (113) of a plurality of on fagging (112), first baffle (113) are located clearing hole (1111) top, just the cross-section of first baffle (113) is the V-arrangement structure, the V-arrangement opening of first baffle (113) is aimed at clearing hole (1111).
8. The system of claim 7, wherein the system comprises: one side of the first baffle (113) far away from the bottom plate (111) is further provided with a plurality of second baffles (114), the second baffles (114) are fixedly connected to the supporting plate (112), the cross sections of the second baffles (114) are of V-shaped structures, and the V-shaped openings of the second baffles (114) and the V-shaped openings of the first baffles (113) are arranged in a staggered mode.
9. The system of claim 8, wherein the system comprises: bottom plate (111) are towards one side rigid coupling of first baffle (113) have injection cover (115), injection cover (115) are the loop configuration that both ends link up, the one end of injection cover (115) is aimed at through hole (1111), leave the clearance between injection cover (115) and bottom plate (111), be provided with on injection cover (115) and connect foot (1151), connect foot (1151) with bottom plate (111) fixed connection.
10. The system of claim 9, wherein the system comprises: the spraying cover (115) is in transition arrangement in a necking shape from one end close to the bottom plate (111) to one end close to the first baffle plate (113).
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Cited By (1)
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| CN116899249A (en) * | 2023-09-13 | 2023-10-20 | 山西诚宏福得一化工有限公司 | Light benzene separation processing device and processing technology thereof |
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